Amateur Radio RF Environment Evaluation Exemption Calculator  
Optional Information    
Enter Frequency in MHz
Calculated Minimum Distance Required (Feet)
Enter Distance to Antenna (Feet) Note: Minimun Distance 7.87"
Calculated - Does Exemption Apply?
Select Coax Type
Enter Length of Coax in feet
Enter Transmitter Power in Watts
Select dBi or dBd and Enter Antenna Gain
Calculated - Effective Radiated Power (ERP) (Watts)
Calculated - Maximum Allowed ERP (Watts)
The Amateur Radio RF Environment Exemption Calculator determines if the FCC
Exemption to Routine Evaluation applies. It also calculates the maximum allowed
Effective Radiated Power (ERP). Enter the frequency and distance to the antenna.
If the calculator indicates that the exemption applies, select the type of coaxial cable,
enter the cable length, transmitter power and antenna gain. The calculator displays
the station's ERP and the maxium allowed power.  Adjust transmitter power
may be adjusted to keep the station's ERP below the maximum allowed.
Note: Stations, not qualifying for an exemption, may still meet the FCC Maximum Permissible
Exposure (MPE) limits by perfoming a RF environmental analysis.  A suggested resource,
with more information is:
Calculation formulas: The exemption applies if, R, the distance between the antenna and human exposure (meters) is greater than the wavelength/2π.  The maximum allowed ERP is determined by the adjacent formulas, where "f" is frequency (MHz).  Frequency (MHz) Maximum ERP (Watts)
0.3 - 1.34 1,920 * R^2
1.34 - 30 3,450 * R^2 / f^2
30 - 300 3.83 / R^2
300 - 1,500 0.0128 * R^2 *f
1,500 - 100,000 19.2 * R^2
This calculator is being made available in support of Amateur Radio activities.
The author assumes no liability or responsibilities for errors or omissions.
Rev 3.7  Authored by KA6UGS.  For questions email: [email protected]